tree:add void *priv argument to tree traversal function and its visit callback
alg:added quicksort source code from glibc and apple
ds.tree:add parent pointer to tree node
tree:rename files
tree:rename struct tree to struct btree,meaning binary tree
tree:mv struct btree to btree.h
tree:add btree.h and bstree.h
tree:add bstree.c
tree:add binary search insert and delete prototype